The electrophotographic photosensitive member mounted on electrophotographic apparatuses includes organic electrophotographic photosensitive members (hereinafter, referred to as an “electrophotographic photosensitive member”) containing an organic charge-generating substance (organic photoconductive substance). In the electrophotographic process, the surface of the electrophotographic photosensitive member contacts a variety of objects such as a developer, a charging member, a cleaning blade, paper, and a transfer member (hereinafter, referred to as a “contacting member and the like”). For this reason, there has been a demand for reduction in deterioration of image quality caused by contact stress when the electrophotographic photosensitive member contacts the contacting member and the like. Particularly, recently, persistency of a reducing effect on deterioration in image quality caused by the contact stress has been demanded of the electrophotographic photosensitive member as the durability of the electrophotographic photosensitive member is improved.
For continuous relaxation of the contact stress, PTL 1 proposes a method in which using a siloxane resin having a siloxane structure incorporated in the molecular chain, a matrix-domain structure is formed in a surface layer. The disclosure shows that using a polyester resin having a specific siloxane structure incorporated, continuous relaxation of the contact stress can be compatible with potential stability (suppression of fluctuation) when the photoreceptor is repeatedly used.
On the other hand, there has been a proposal that a siloxane modified resin having a siloxane structure in the molecular chain is added to the surface layer of the electrophotographic photosensitive member. PTL 2 proposes an electrophotographic photosensitive member containing a polycarbonate-siloxane copolymerized resin having a specific siloxane structure incorporated, and reports that wear resistance and contamination resistance are improved by introduction of the siloxane structure.